It's quite difficult to eliminate existing error fields, so instead of fixing these coil irregularities, researchers can apply additional magnetic fields surrounding the fusion vessel in a process known as error field correction.
In the past, this approach would have also hurt the plasma's core, making the plasma unsuitable for fusion power generation. This time, the researchers were able to eliminate instabilities at the edge of the plasma and maintain the stability of the core. The research is a prime example of how PPPL researchers are bridging the gap between today's fusion technology and what will be needed to bring fusion power to the electrical grid.

"This is actually a very effective way of breaking the symmetry of the system, so humans can intentionally degrade the confinement. It's like making a very tiny hole in a balloon so that it will not explode.
One of the toughest parts of managing a fusion reaction is getting both the core and the edge of the plasma to behave at the same time. There are ideal zones for the temperature and density of the plasma in both regions and hitting those targets while eliminating instabilities is tough.

This study demonstrates that adjusting the error fields can simultaneously stabilize both the core and the edge of the plasma. By carefully controlling the magnetic fields produced by the tokamak's coils, the researchers could suppress edge instabilities, also known as edge localized modes (ELMs), without causing disruptions or a substantial loss of confinement.

 SeongMoo Yang et al, Tailoring tokamak error fields to control plasma instabilities and transport, Nature Communications (2024). DOI: 10.1038/s41467-024-45454-1

The Arctic could become 'ice-free' within a decade, say scientists

The Arctic could see summer days with practically no sea ice as early as the next couple of years, according to a new study .

The findings, published in the journal Nature Reviews Earth & Environment, suggest that the first ice-free day in the Arctic could occur over 10 years earlier than previous projections, which focused on when the region would be ice-free for a month or more. The trend remains consistent under all future emission scenarios.

By mid-century, the Arctic is likely to see an entire month without floating ice during September, when the region's sea ice coverage is at its minimum. At the end of the century, the ice-free season could last several months a year, depending on future emissions scenarios. For example, under a high-emissions, or business-as-usual, scenario, the planet's northernmost region could become consistently ice-free even in some winter months.

For scientists, an ice-free Arctic doesn't mean there would be zero ice in the water.

Instead, researchers say the Arctic is ice-free when the ocean has less than 1 million square kilometers (386,000 square miles) of ice. The threshold represents less than 20% of what the region's seasonal minimum ice cover was in the 1980s. In recent years, the Arctic Ocean had around 3.3 million square kilometers of sea ice area at its minimum in September.

Projections of an ice-free Arctic Ocean, Nature Reviews Earth & Environment (2024). DOI: 10.1038/s43017-023-00515-9

Organoids grown from amniotic fluid
For the first time, researchers have grown organoids — 3D bundles of cells that mimic tissue — directly from cells taken from ongoing pregnancies. The cells were extracted from amniotic fluid around growing fetuses between the 16th and 34th weeks of gestation during standard procedures independent of the study. The team grew organoids from three organs — the small intestines, kidneys and lungs — and also modelled congenital diaphragmatic hernia, a disorder where the diaphragm fails to develop correctly, using cells from samples affected by the disorder. Unlike organoids made from pluripotent stem cells, the amniotic fluid cells already have an organ identity. “There is no reprogramming, no manipulation,” says stem-cell biologist and study co-author Mattia Gerli, “we’re just allowing the cells to express their potential.”

https://www.nature.com/articles/d41586-024-00656-x?utm_source=Live+...

https://www.nature.com/articles/s41591-024-02807-z?utm_source=Live+...

Physicists Reveal a Strange Form of Crystal Where Electrons Can't Move

In a search for novel materials that can contain bizarre new states of matter, physicists led an experiment that forced free-roaming electrons to stay in place. While the phenomenon has been seen in materials where electrons are constrained to just two dimensions, this is the first time it's been observed in a three-dimensional crystal metal lattice, known as a pyrochlore. The technique gives researchers a new tool for studying the less conventional activities of plucky, charge-carrying particles.

https://www.nature.com/articles/s41567-023-02362-3

New 'Water Batteries' Are Cheaper, Recyclable, And Won't Explode

Water and electronics don't usually mix, but as it turns out, batteries could benefit from some H₂O.

By replacing the hazardous chemical electrolytes used in commercial batteries with water, scientists have developed a recyclable 'water battery' – and solved key issues with the emerging technology, which could be a safer and greener alternative.

'Water batteries' are formally known as aqueous metal-ion batteries. These devices use metals such as magnesium or zinc, which are cheaper to assemble and less toxic than the materials currently used in other kinds of batteries.

Batteries store energy by creating a flow of electrons that move from the positive end of the battery (the cathode) to the negative end (the anode). They expend energy when electrons flow the opposite way. The fluid in the battery is there to shuttle electrons back and forth between both ends.

In a water battery, the electrolytic fluid is water with a few added salts, instead of something like sulfuric acid or lithium salt.

Crucially, the team behind this latest advancement came up with a way to prevent these water batteries from short-circuiting. This happens when tiny spiky metallic growths called dendrites form on the metal anode inside a battery, busting through battery compartments.

https://onlinelibrary.wiley.com/doi/10.1002/adma.202400237

Scientists CT scanned thousands of natural history specimens, which you can access for free

Natural history museums have entered a new stage of scientific discovery and accessibility with the completion of openVertebrate (oVert), a five-year collaborative project among 18 institutions to create 3D reconstructions of vertebrate specimens and make them freely available online.

Researchers published a summary of the project in the journal BioScience in which they review the specimens that have been scanned to date and offer a glimpse of how the data might be used to ask new questions and spur the development of innovative technology.

Scientists, teachers, students and artists around the world are using these data remotely now.

David Blackburn et al, Increasing the impact of vertebrate scientific collections through 3D-imaging: the openVertebrate (oVert) Thematic Collections Network, BioScience (2023). DOI: 10.1093/biosci/biad120. academic.oup.com/bioscience/ad … osci/biad120/7615104

Birds, beetles, bugs could help replace pesticides

Natural predators like birds, beetles and bugs might be an effective alternative to pesticides, keeping crop-devouring pests populations down while boosting crop yields, researchers say.

Pests are responsible for around 10 percent—or 21 million metric tons—of crop losses every year, but controlling them has led to the widespread use of chemical pesticides. Could birds, spiders and beetles among other invertebrate predators do the job as well?

Researchers in Brazil, the United States and the Czech Republic analyzed past research on predator pest control and found that they helped reduce pest populations by more than 70 percent, while increasing crop yields by 25 percent.

Natural predators are good pest control agents, and their maintenance is fundamental to guaranteeing pest control in a future with imminent climate change, according to scientists.

Although the researchers did not directly compare the effectiveness of invertebrates versus pesticides, he said, the damage that pesticides cause to ecosystems and biological control was well documented, from biodiversity loss and water and soil pollution to human health risks.
The researchers found that predators were more effective at pest control in regions with greater rain variability—which is expected to increase because of climate change.

The researchers were also surprised to find that having a single species of natural predator was as effective as having multiple species.
Generally speaking, the more species there are, the better ecosystems function. But there are exceptions: a single species could do the job just as well.
Climate change and rising carbon dioxide levels affect both crop yield and pest dynamics by expanding the distribution of pests and increasing their survival rates.

Meanwhile, other studies have shown that invertebrates vital for ecosystem health are suffering a rapid decline globally.
The conservation of invertebrates "guarantees pest control and increased productivity, without damaging ecosystems".
Source: AFP and other news agencies
https://phys.org/news/2024-03-birds-beetles-bugs-pesticides.html?ut...

https://phys.org/tags/biological+control/

Model estimates who benefits most from frequent COVID-19 boosters

Patients keep asking a question : How often should I get my booster shot for COVID-19?

So scientists built a model to answer that question. They published a study describing that model and its results in the journal Nature Communications.

The model's results largely square with data on who is most at risk of bad outcomes from COVID-19: For those older than 65 or who are immunocompromised, more frequent boosters—at least annually—go further to protect against hospitalization or death. For younger populations, the benefit of frequent boosting against severe disease is more modest.

The researchers hope this model can help inform both individuals making decisions about when to get boosters as well as public health policy makers.

For those over 75 years, receiving a yearly booster reduced annual severe infections from around 1,400 cases per 100,000 people to about 1,200 cases. Bumping the booster up to twice a year dropped severe infections to just over 1,000 per 100,000.

The numbers are similar for those who are moderately or severely immunocompromised, and about half that reduction for those aged 65 to 74. For younger, healthy people, the drop is much smaller: Annual or twice-yearly boosters reduced severe infections in people aged 18 to 49 by only 14 to 26 cases per 100,000 people.

These high-risk populations benefit from more frequent boosters relative to younger and healthier individuals.

Hailey J. Park et al, Comparing frequency of booster vaccination to prevent severe COVID-19 by risk group in the United States, Nature Communications (2024). DOI: 10.1038/s41467-024-45549-9

Scientists use a new type of nanoparticle that can both deliver vaccines and act as an adjuvant

Many vaccines, including vaccines for hepatitis B and whooping cough, consist of fragments of viral or bacterial proteins. These vaccines often include other molecules called adjuvants, which help to boost the immune system's response to the protein.

Most of these adjuvants consist of aluminum salts or other molecules that provoke a nonspecific immune response. A team of  researchers has now shown that a type of nanoparticle called a metal organic framework (MOF) can also provoke a strong immune response, by activating the innate immune system—the body's first line of defense against any pathogen—through cell proteins called toll-like receptors.

In a study of mice, the researchers showed that this MOF could successfully encapsulate and deliver part of the SARS-CoV-2 spike protein,  while also acting as an adjuvant once the MOF is broken down inside cells.

While more work would be needed to adapt these particles for use as vaccines, the study demonstrates that this type of structure can be useful for generating a strong immune response, the researchers say.

Understanding how the drug delivery vehicle can enhance an adjuvant immune response is something that could be very helpful in designing new vaccines.

Shahad Alsaiari et al, Zeolitic Imidazolate Frameworks Activate Endosomal Toll-like Receptors and Potentiate Immunogenicity of SARS-CoV-2 Spike Protein Trimer, Science Advances (2024). DOI: 10.1126/sciadv.adj6380. www.science.org/doi/10.1126/sciadv.adj6380

Nanodevices can produce energy from evaporating tap or seawater

Evaporation is a natural process so ubiquitous that most of us take it for granted. In fact, roughly half of the solar energy that reaches the Earth drives evaporative processes. Since 2017, researchers have been working to harness the energy potential of evaporation via the hydrovoltaic (HV) effect, which allows electricity to be harvested when fluid is passed over the charged surface of a nanoscale device.

Evaporation establishes a continuous flow within nanochannels inside these devices, which act as passive pumping mechanisms. This effect is also seen in the microcapillaries of plants, where water transport occurs thanks to a combination of capillary pressure and natural evaporation.

Although hydrovoltaic devices currently exist, there is very little functional understanding of the conditions and physical phenomena that govern HV energy production at the nanoscale.

To bridge that gap, researchers now leveraged a combination of experiments and multiphysics modeling to characterize fluid flows, ion flows, and electrostatic effects due to solid-liquid interactions, with the goal of optimizing HV devices.

 In the process, they also made a major finding: that hydrovoltaic devices can operate over a wide range of salinities, contradicting prior understanding that highly purified water was required for best performance.

Part 1

The researchers' device represents the first hydrovoltaic application of a technique called nanosphere colloidal lithography, which allowed them to create a hexagonal network of precisely spaced silicon nanopillars. The spaces between the nanopillars created the perfect channels for evaporating fluid samples and could be finely tuned to better understand the effects of fluid confinement and the solid/liquid contact area.

In most fluidic systems containing saline solutions, you have an equal number of positive and negative ions. However, when you confine the liquid to a nanochannel, only ions with a polarity opposite to that of the surface charge will remain. This means that if you allow liquid to flow through the nanochannel, you will generate current and voltages.

As the fluid ion concentration increases, so does the surface charge of the nanodevice. As a result, we can use larger fluid channels while working with higher-concentration fluids. This makes it easier to fabricate devices for use with tap or seawater, as opposed to only purified water.

Because evaporation can occur continuously over a wide range of temperatures and humidities—and even at night—there are many exciting potential applications for more efficient HV devices.

Tarique Anwar et al, Salinity-dependent interfacial phenomena toward hydrovoltaic device optimization, Device (2024). DOI: 10.1016/j.device.2024.100287

Part 2

COVID protections wiped out a strain of flu
For the first time, an influenza virus has been eliminated from the human population through non-pharmaceutical interventions. The public-health protections brought in during the COVID-19 pandemic — such as wearing a mask, social distancing and better ventilation — seem to have eliminated the influenza B/Yamagata lineage; no cases have been confirmed since March 2020. In September, the World Health Organization recommended that countries no longer include Yamagata-lineage antigens in flu vaccines, and US Food and Drug Administration advisors have now voted to remove it from flu jabs in the United States.

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(23)00697-7/fulltext?utm_source=Live+Audience&utm_campaign=c98e4d006c-briefing-dy-20240306&utm_medium=email&utm_term=0_b27a691814-c98e4d006c-50323416

https://edition.cnn.com/2024/03/05/health/flu-vaccine-yamagata-stra...

https://www.nature.com/articles/s41380-023-02382-8

For childhood cancer survivors, inherited genetic factors influence risk of cancers later in life

Common inherited genetic factors that predict cancer risk in the general population may also predict elevated risk of new cancers among childhood cancer survivors, according to a study  by researchers .

The findings, published in Nature Medicine, provide additional evidence that genetics may play an important role in the development of subsequent cancers in survivors of childhood cancer and suggest that common inherited variants could potentially inform screening and long-term follow-up of those at greatest risk. Childhood cancer survivors are known to have a higher risk of developing a new cancer later in life due to adverse effects of cancer treatment or rare inherited genetic factors.

In the new study, the researchers evaluated the combined effect of common variants with history of radiation treatment and found the resulting elevated cancer risk was greater than the sum of the individual associations for treatment and genetic factors alone.

Polygenic risk scores, radiation treatment exposures and subsequent cancer risk in childhood cancer survivors, Nature Medicine (2024).

Plastic pollution's effect on heart health

We breathe, eat and drink tiny particles of plastic. But are these minuscule specks in the body harmless, dangerous or somewhere in between?

A small study published recently in the New England Journal of Medicine raises more questions than it answers about how these bits—microplastics and the smaller nanoplastics—might affect the heart. The Italian study has weaknesses, but is likely to draw attention to the debate over the problem of plastic pollution. Most plastic waste is never recycled and breaks down into these particles.

It's a wake-up call that perhaps we need to take the problem of microplastics more seriously. As a cause for heart disease? Not proven. As a potential cause? Maybe!

The study involved 257 people who had surgery to clear blocked blood vessels in their necks. Italian researchers analyzed the fatty buildup that the surgeons removed from the carotid arteries, which supply blood and oxygen to the brain.

Using two methods, they found evidence of plastics—mostly invisible nanoplastics—in the artery plaque of 150 patients and no evidence of plastics in 107 patients.

They followed these people for three years. During that time, 30 or 20% of those with plastics had a heart attack, stroke or died from any cause, compared to eight or about 8% of those with no evidence of plastics.

The researchers also found more evidence of inflammation in the people with the plastic bits in their blood vessels. Inflammation is the body's response to injury and is thought to raise the risk of heart attacks and strokes.

It's very small and looked only at people with narrowed arteries, who were already at risk for heart attack and stroke. The patients with the plastics had more heart disease, diabetes and high cholesterol than the patients without plastics. They were more likely to be men and more likely to be smokers.

The researchers tried to adjust for these risk factors during their statistical analysis, but they may have missed important differences between the groups that could account for the results. This kind of study cannot prove that the plastics caused their problems.

The researchers had no information on what the people consumed or breathed that might account for the plastics.

The specimens could have been contaminated in the lab. The researchers acknowledge as much in their paper and suggest that future studies be done in clean rooms where air is filtered for pollutants.

The researchers suggest the risk of heart attack, stroke or death was four times greater in the people with the plastics. That seems high.

More research is needed as it does not prove cause and effect, but it suggests cause and effect. And it needs urgently to be either replicated or disproven by other studies done by other investigators in other populations.

This just makes us more alert to the problem.

Raffaele Marfella et al, Microplastics and Nanoplastics in Atheromas and Cardiovascular Events, New England Journal of Medicine (2024). DOI: 10.1056/NEJMoa2309822

Philip J. Landrigan, Plastics, Fossil Carbon, and the Heart, New England Journal of Medicine (2024). DOI: 10.1056/NEJMe2400683

**

Bull's-Eye Cancer Treatment
A promising new class of cancer drugs is gaining momentum. Antibody-drug conjugates, or ADCs, target specific hormone receptors on cancer cells and deliver growth-stopping drugs directly to tumors. Fourteen ADCs have been approved for breast, bladder, ovarian, blood, and other cancers, some difficult to treat with traditional tactics. About 100 other ADCs are in the preclinical pipeline.

How these drugs are different: Traditional chemotherapeutic drugs kill cancer cells, but also kill healthy cells in the process, leading to severe side effects in the patient. Because of the debilitating side effects, most patients cannot endure a maximum dose of chemotherapy. ADC technology could also be used to deliver radiation therapy directly to tumor cells, or deliver drugs that activate the patient’s immune system to eradicate the cancer.

What the experts say: Enhertu, a new ADC treatment for breast cancer that uses special molecules to link the antibody to the drug that targets cancer cells, has been shown to stop cancer growth for four times longer than a compound without the linker molecules. “It was a landslide in terms of how much better it was,” says oncologist Sara M. Tolaney of the Dana-Farber Cancer Institute in Boston. “It's a really nice example of how ADC technology leads to dramatic differences in outcomes.”

deliver growth-stopping drugs directly to tumors.

'Double life' of key immune protein reveals new strategies for treating cancer and autoimmune diseases

Insights into the workings of an immune cell surface receptor, called PD-1, reveal how treatments that restrict its action can potentially be strengthened to improve their anticancer effect, a new study shows. The same findings also support experimental treatment strategies for autoimmune diseases, in which the immune system attacks the body, because stimulating the action of PD-1, as opposed to restricting it, can potentially block an overactive immune response.

The study is published  in the journal Science Immunology.

The study results revolve around the body's immune system, which is primed to attack virally infected and cancerous cells while leaving normal cells alone. To spare normal cells from immune attack, the system uses "checkpoints," sensors on the surface of immune cells, including T cells, which turn them off or dampen activation when they receive the right signal. The immune system recognizes tumors as abnormal, but cancer cells can hijack checkpoints to turn off immune responses.

Among the most important checkpoints is a protein called programmed cell death receptor 1 (PD-1), which is shut down by a relatively new drug class called checkpoint inhibitors to make tumors "visible" again to immune attack. Such drugs are at least somewhat effective in a third of patients with a variety of cancers, say the study authors, but the field is urgently seeking ways to improve their performance and scope.

Many immune checkpoints are receptors on the surface of T cells that act to translate docking information from the outside of the cell to the signaling portion of the receptor inside the cell. Connecting the outside-of-the-cell portion of PD-1 with the inside portion is the transmembrane segment. Many immune receptors function in pairs called dimers, but to date, PD-1 has been thought to function alone, not in the dimer form.

Study results showed that PD-1 forms a dimer through interactions of its transmembrane segment. Researchers say this finding is in sharp contrast to other immune receptors, which typically form dimers through the segment of the receptor that is outside the cell.

Further immune cell testing in mice showed that encouraging PD-1 to form dimers, specifically in the transmembrane domain but not in its outer or inner regions, increased its ability to suppress T cell activity, while decreasing transmembrane dimerization lowered PD-1's ability to inhibit immune cell activity.

The study reveals that the PD-1 receptor functions optimally as dimers driven by interactions within the transmembrane domain on the surface of T cells, contrary to the dogma that PD-1 is a monomer.

These findings offer new insights into the molecular workings of the PD-1 immune cell protein that have proven pivotal to the development of the current generation of anticancer immunotherapies, and which are proving essential in the design and developing of the next generation of immunotherapies for autoimmune diseases.

Among the study's other findings was that a single change in the amino acid structure of the transmembrane segment can act to either enhance or diminish the inhibitory function of PD-1 in immune responses.

The team plans further investigations of PD-1 inhibitors and agonists to see if they can tailor what they say are more effective, "rationally designed" therapies for both cancer and autoimmune disorders.

Elliot Philips et al, Transmembrane Domain Driven PD-1 Dimers Mediate T Cell Inhibition, Science Immunology (2024). DOI: 10.1126/sciimmunol.ade6256. www.science.org/doi/10.1126/sciimmunol.ade6256

Part 2

Water guides the assembly of collagen, the building block of all humans

Water determines life: humans are three-quarters water. An international research team  has now discovered how water also determines the structure of the material that holds us together: collagen.

In a paper published in PNAS, the researchers elucidate the role of water in the molecular self-assembly of collagen. They show that by replacing water with its 'twin molecule' heavy water (D₂O), one can 'tune' the interaction between collagen molecules, and thus influence the process of collagen self-assembly. The findings will help to better understand the tissue failures resulting from heritable collagen-related diseases, such as brittle bone disease (osteogenesis imperfecta).

Collagen is to a large extent 'the stuff we're made of'—around a third of all protein in our body is collagen which ensures the mechanical integrity of all human connective tissue.

For instance, our skin and arteries stretch without tearing and our bones can resist high stress without breaking. Collagen is produced by our cells as single proteins that assemble into larger structures called fibrils. These fibrils further assemble into networks that form the scaffolds for our tissues.

Since collagen is formed in the aqueous environment of human cells, water plays a crucial role in its assembly. The interaction of water molecules with proteins results in collagen that is best suited for its function. But what exactly is behind this collagen-optimizing role of water? How does water do it? And will understanding this mechanism offer insights into conditions where something is wrong with collagen, such as osteogenesis imperfecta? These were the central questions of the research published in PNAS.

Part 1

To investigate the role of water in collagen formation, researchers decided to replace water with its heavier 'twin molecule' D₂O. 

However, in interaction with proteins, D₂O is less potent than H₂O. This is because bonds between D₂O molecules (so-called hydrogen-bonds) are stronger than those between H₂O molecules. This affects the interaction with proteins such as collagen.

Researchers were keen to study the effect this would have on collagen assembly. Together with a multi-disciplinary collaborative research network, they were able to establish that the use of heavy water results in ten times faster collagen formation, and ultimately a less homogeneous, softer and less stable collagen-fiber network.

The explanation is that the reduced interaction of the heavy water with the collagen protein makes it easier for the protein to 'shake off' the D₂O molecules and reorganize itself.

This boosts the formation of the collagen network, but also results in a sloppier, less optimal collagen network. Water thus acts as a mediator between collagen molecules, slowing down the assembly to guarantee the functional properties of living tissues.

This discovery offers fresh perspectives on how water influences the characteristics of collagen, allowing for precise adjustments in the mechanical properties of living tissues. It also creates novel avenues for creating collagen-based materials where macroscopic properties can be controlled and fine-tuned by subtle variations in the composition of the solvent, rather than making significant changes to the chemical structure of the molecular building blocks.

 Giulia Giubertoni et al, Elucidating the role of water in collagen self-assembly by isotopically modulating collagen hydration, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2313162121

Part 2

**

Altered protein folding drives multicellular evolution

Researchers have discovered a mechanism steering the evolution of multicellular life. They identified how altered protein folding drives multicellular evolution.

In a new study led by researchers, they turned to a tool called experimental evolution. In the ongoing Multicellularity Long Term Evolution Experiment (MuLTEE), laboratory yeast are evolving novel multicellular functions, enabling researchers to investigate how they arise.

The study, published in Science Advances, puts the spotlight on the regulation of proteins in understanding evolution.

By demonstrating the effect of protein-level changes in facilitating evolutionary change, this work highlights why knowledge of the genetic code in itself does not provide a full understanding of how organisms acquire adaptive behaviours. Achieving such understanding requires mapping the entire flow of genetic information, extending all the way to the actionable states of proteins that ultimately control the behaviour of cells.

Among the most important multicellular innovations is the origin of robust bodies: over 3,000 generations, these 'snowflake yeast' started out weaker than gelatin but evolved to be as strong and tough as wood.

Researchers identified a non-genetic mechanism at the base of this new multicellular trait, which acts at the level of protein folding. The authors found that the expression of the chaperone protein Hsp90, which helps other proteins acquire their functional shape, was gradually turned down as snowflake yeast evolved larger, tougher bodies.

It turns out Hsp90 acted as a critically-important tuning knob, destabilizing a central molecule that regulates the progression of the cell cycle, causing cells to become elongated. This elongated shape, in turn, allows cells to wrap around one another, forming larger, more mechanically tough multicellular groups.

From an evolutionary perspective, this work highlights the power of non-genetic mechanisms in rapid evolutionary change.

 Kristopher Montrose et al, Proteostatic tuning underpins the evolution of novel multicellular traits, Science Advances (2024). DOI: 10.1126/sciadv.adn2706. www.science.org/doi/10.1126/sciadv.adn2706

Horizontal gene transfer: How fungi improve their ability to infect insects

Researchers have investigated for the first time in detail how a fungus important for biological plant protection can pass on an advantageous chromosome horizontally, using a previously little-studied way of exchanging genetic information.

Sustainable plant protection measures that are not based on chemical pesticides rely on various organisms and biological agents to protect crops from pests. Such organisms used for biological plant protection are, for example, microscopic fungi of the genus Metarhizium, which can attack and kill a variety of plant-pathogenic insects and are used, for example, in South American sugar cane cultivation.

The molecular mechanisms of fungal infection and the immune response of insects are in an ongoing process of mutual evolutionary adaptation.

The researchers examined the genomes of different strains of the fungi Metarhizium robertsii and Metarhizium brunneum from an earlier co-infection experiment in which ants had been infected with the fungus mix.

In the study, the outgrowing spores were used to infect new ants over 10 consecutive infection cycles. When analyzing the fungal genomes from these infection series, researchers made an exciting observation:  the analyses showed that a single chromosome was very frequently exchanged horizontally between two different strains.

This chromosome contains certain genes that the scientists suspect may give the fungus an advantage in infecting its hosts. The horizontal transfer of entire chromosomes has rarely been described scientifically and has now been studied in detail for the first time. The researchers from the Kiel Evolution Center (KEC) and ISTA published their results in the journal Proceedings of the National Academy of Sciences.

Part 1

Scientists use the term horizontal gene transfer to describe how living organisms can transfer genetic material between different individuals, including those of other species. In this way, bacteria exchange extensive genetic information, often in the form of plasmids, in order to quickly adapt to changing environmental conditions or to adapt to the host. The rapid evolution of various pathogens is based on such mechanisms, among other things.

In fungi and many other so-called eukaryotic organisms, however, horizontal gene transfer in the form of entire chromosomes is very rare.

The analysis of the genetic information of the fungal strains shows that M. robertsii independently transferred a single chromosome a total of five times during the co-infection experiments, but no other genetic information from one strain to another via horizontal transfer.

Further analyses also indicated that the same chromosome can also be found in the distantly related, also insect-damaging fungus species Metarhizium guizhouense, whose common evolutionary origin with M. robertsii dates back around 15 million years.

The chromosome in M. guizhouense is significantly less altered than would be assumed for the long period of separate evolution of the two fungal species. The chromosome therefore also appears to have been passed on naturally between these different fungal species—and probably horizontally.

The experiments showed that, under certain conditions, the fungus that had received the accessory chromosome had competitive advantages over fungi of the same strain that had not received the chromosome and were able to prevail against them.

The transfer of the chromosome may therefore have advantages for the fungus, the functional basis of which is still unclear. However, one plausible possibility is the transfer of certain genes that produce chitin-cleaving enzymes and can thus improve the ability to infect the insects.

Michael Habig et al, Frequent horizontal chromosome transfer between asexual fungal insect pathogens, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2316284121

Egg-laying caecilian amphibians produce milk for their young, find scientists

Parental care for offspring occurs in many animals and is an essential part of the reproduction, propagation and development of an organism. An international research team has revealed for the first time how egg-laying female caecilian amphibians successfully raise their offspring in the nest.

Caecilian amphibians are one of the least known vertebrate groups. The researchers were able to observe that the females of egg-laying amphibians, such as the species Siphonops annulatus, provide their young a similarly high-fat milk in the nest as, for example, egg-laying mammals. This discovery demonstrates the complexity of the evolution of reproductive strategies in vertebrates and expands our knowledge of brood care and communication in amphibians.

The research is published in the journal Science.

In most vertebrates, the yolk is usually the only form of nutrition females provide to the growing embryo. The research team observed that the young of the Brazilian caecilian Siphonops annulatus consumed milk for over two months, which appears to be secreted in response to tactile and acoustic stimulation from the mother's cloaca. The milk consists mainly of fats and carbohydrates and is produced in the glands of the female's oviduct.

Scientists have now discovered a vertebrate system in amphibians that has developed similarly comprehensive brood care mechanisms as known for mammals. This includes the production of fat-rich mother's milk and the release of milk to the young in the nest, known as lactation. This tells us a lot about the evolution and reproductive strategies of this still little-known vertebrate order.

Caecilian amphibians are legless, snake-like amphibians that are widespread in the tropical regions of the world. All caecilian amphibians provide brood care. The female of the Brazilian amphibian Siphonops annulatus lays eggs and raises its hatchlings in the nest with fat-rich "milk" as well as its skin. Parental brood care is therefore similar to that of egg-laying mammals such as echidnas and platypuses.

Pedro L. Mailho-Fontana et al, Milk provisioning in oviparous caecilian amphibians, Science (2024). DOI: 10.1126/science.adi5379

Ebola-fighting potential of engineered bacteria

The  Ebola virus has proven an especially lethal contagion, killing roughly 50% of the people who contract it. The 2019 FDA approval of a vaccine, combined with the subsequent development of two antibody-based drugs, marked unprecedented progress against one species of the virus. Yet the continuing threat posed by several other types of Ebola has left researchers in pursuit of additional treatments—particularly in developing regions of Africa, where limited infrastructure can impede the storage and deployment of vaccines.

One approach to combating viral threats has come in the form of a microbial counterpart: bacteria. In researching inhibitors of HIV, for instance, some researchers identified the promise of lectins, or bacteria-generated proteins that can selectively bind to the surfaces of viral particles, thereby neutralizing them.

Scientists took a special interest in scytovirin, a type of lectin produced by cyanobacteria, likely the Earth's first oxygen-producing organisms. Because scytovirin had shown some early success in inhibiting Ebola, they went about engineering two strains of lactic acid bacteria, which can safely colonize the human body, to display scytovirin on their own surfaces. The study is published in the journal Frontiers in Microbiology.

After constructing research-safe shells of Ebola particles, the virologists introduced them to the two bacterial strains. Their experiments revealed that one of the engineered strains, Lactococcus lactis, could neutralize roughly 54% of the Ebola particles—more than twice the rate of scytovirin-free L. lactis.

The research team  is now testing the bacteria-delivered antiviral in mice, where the virologists are determining whether the engineered L. lactis can neutralize Ebola the way it did in cell cultures. Passing that test could eventually lead to human trials.

If it does continue to perform, L. lactis—which is already used to make cheese and buttermilk—could become a relatively simple, inexpensive, long-term way to protect vulnerable populations against the devastating virus, the team said.

Joshua Wiggins et al, Lactic acid bacterial surface display of scytovirin inhibitors for anti-ebolavirus infection, Frontiers in Microbiology (2023). DOI: 10.3389/fmicb.2023.1269869

Researchers develop artificial building blocks of life

For the first time, scientists  have developed artificial nucleotides, the building blocks of DNA, with several additional properties in the laboratory, which could be used as artificial nucleic acids for therapeutic applications.

DNA carries the genetic information of all living organisms and consists of only four different building blocks, the nucleotides. Nucleotides are composed of three distinctive parts: a sugar molecule, a phosphate group, and one of the four nucleobases adenine, thymine, guanine, and cytosine.

The nucleotides are lined up millions of times and form the DNA double helix, similar to a spiral staircase. Scientists have now shown that the structure of  nucleotides can be modified to a great extent in the laboratory. The researchers developed so-called threofuranosyl nucleic acid (TNA) with a new, additional base pair.

But artificial nucleic acids differ in structure from their originals. These changes affect their stability and function.  However,  threofuranosyl nucleic acid is more stable than the naturally occurring nucleic acids DNA and RNA, which brings many advantages for future therapeutic use.

These are the first steps on the way to fully artificial nucleic acids with enhanced chemical functionalities. The study "Expanding the Horizon of the Xeno Nucleic Acid Space: Threose Nucleic Acids with Increased Information Storage' was published in the Journal of the American Chemical Society.

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For the study, the 5-carbon sugar deoxyribose, which forms the backbone of DNA, was replaced by a 4-carbon sugar. In addition, the number of nucleobases was increased from four to six. By exchanging the sugar, the TNA is not recognized by the cell's own degradation enzymes. This has been a problem with nucleic acid-based therapeutics, as synthetically produced RNA that is introduced into a cell is rapidly degraded and loses its effect.

The introduction of TNAs into cells that remain undetected could now maintain the effect for longer. "In addition, the built-in unnatural base pair enables alternative binding options to target molecules in the cell.

TNAs could also be used for the targeted transport of drugs to specific organs in the body (targeted drug delivery) as well as in diagnostics; they could also be useful for the recognition of viral proteins or biomarkers.

Hannah Depmeier et al, Expanding the Horizon of the Xeno Nucleic Acid Space: Threose Nucleic Acids with Increased Information Storage, Journal of the American Chemical Society (2024). DOI: 10.1021/jacs.3c14626

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Australia's Great Barrier Reef in grip of 'mass bleaching event'

A "mass bleaching event" is unfolding on Australia's famed Great Barrier Reef, authorities said recently, as warming seas threaten the spectacular home to thousands of marine species.

Listen to a star ‘twinkle’

A look inside the Harvard Herbaria

For people who speak many languages, there's something special about their native tongue

A new study of people who speak many languages has found that there is something special about how the brain processes their native language.

In the brains of these polyglots—people who speak five or more languages ( I am one of them too!)—the same language regions light up when they listen to any of the languages that they speak. In general, this network responds more strongly to languages in which the speaker is more proficient, with one notable exception: the speaker's native language. When listening to one's native language, language network activity drops off significantly.

The findings suggest there is something unique about the first language one acquires, which allows the brain to process it with minimal effort, the researchers say.

Something makes it a little bit easier to process—maybe it's that you've spent more time using that language—and you get a dip in activity for the native language compared to other languages that you speak proficiently.

The brain's language processing network, located primarily in the left hemisphere, includes regions in the frontal and temporal lobes. In a 2021 study, researchers found that in the brains of polyglots, the language network was less active when listening to their native language than the language networks of people who speak only one language.

In the new study, the researchers wanted to expand on that finding and explore what happens in the brains of polyglots as they listen to languages in which they have varying levels of proficiency. Studying polyglots can help researchers learn more about the functions of the language network, and how languages learned later in life might be represented differently than a native language or languages.

With polyglots, you can do all of the comparisons within one person. You have languages that vary along a continuum, and you can try to see how the brain modulates responses as a function of proficiency.

Saima Malik-Moraleda et al, Functional characterization of the language network of polyglots and hyperpolyglots with precision fMRI, Cerebral Cortex (2024). DOI: 10.1093/cercor/bhae049

False GPS signal surge makes life hard for pilots

False GPS signals that deceive on-board plane systems and complicate the work of airline pilots are surging near conflict zones.

A ground collision alert sounds in the cockpit, for instance, even though the plane is flying at high altitude—a phenomenon affecting several regions and apparently of military origin.

This includes the vicinity of Ukraine following the Russian invasion two years ago, the eastern Mediterranean and the air corridor running above Iraq, according to pilots and officials.

Disruptions which were previously limited to jamming preventing access to signals from geolocation satellites are now also taking a more dangerous form making it difficult to counter spoofing.

This sees a plane receive false coordinates, times and altitudes.

By comparing this data to the geographical maps in its memory banks, its systems can conclude there is imminent danger ahead. There were some untimely alarms ordering people to pull back as far as possible on the stick and apply full power to avoid an obstacle, while the plane was in cruise... and in any case no mountain reaches so high.

The problem  is that this adulterated information enters the navigation system and can cause false alerts hours afterwards as the flight nears its destination.

At first, crews quickly see that it is a false alarm. But as it is an alarm warning of immediate danger, control towers ask the crews to still carry out the emergency maneuver, to make a return and an analysis. If the problem occurs a second time and the analysis has not revealed any danger, then the only way is to turn off this alarm, knowing other systems remain active to detect possible risk.

Since the start of the war in Ukraine, the European Union Aviation Safety Agency (EASA) has been warning that GNSS signal disruptions have intensified, affecting relatively remote regions beyond the conflict zone such as Finland and the Mediterranean.

In certain cases, this can lead to a modified trajectory or even a changed destination as it was impossible to carry out a landing in secure conditions, the EASA says.

Source: AFP and other news agencies

Spring irrigation can reduce summer heat wave events

Heat waves are becoming more extreme as climate change exacerbates, with susceptible locations experiencing more frequent, prolonged and higher intensity events. As such, they pose a hazard to agricultural practices that rely upon sufficient water to ensure sustainable food supplies.

Irrigation is used to help alleviate warm, dry climates by maintaining soil moisture levels to promote growth as well as exerting a cooling effect on the immediate local climate (within a few meters of the surface), but extracts freshwater from resources that may also be threatened by shrinkage with more evaporation in a warmer world.

New research, published in Geophysical Research Letters, has investigated the dampening effect irrigating land in spring can have on the intensity of summer heat waves by retaining higher soil moisture levels between seasons, known as soil moisture memory.

The researchers  analyzed models of root-zone soil moisture data from 1980 to 2018 and combined this with a forecasting model to simulate the effect of irrigation on extreme summer heat wave events from 2004 to 2018. They ran three tests, one with no irrigation, one with both spring and summer irrigation, and the last solely with spring irrigation.

The researchers found that spring irrigation reduced the intensity of summer heat waves by 0.29°C and 2.5 days, and when combined with summer irrigation this extends to a reduction of 1°C and 6.5 days. With the simulated regional means of extreme heat waves being temperatures of 35.8°C and lasting 21.7 days, the combined impact of spring and summer irrigation can have a significant effect, especially on the longevity of the event.

This research is important as it suggests applying a surplus of water in spring helps to alleviate water stress in the following summer months, and is less wasteful of water resources that evaporate more in summer (especially from the top 1 m of soil), while also supporting regions that experience an imbalance in precipitation through the year.

Though the intensity of extreme heat wave events may be reduced, these climatic challenges will persist in the future, so it is important to apply these results in water resource management and adaptation planning strategies.

Guoshuai Liu et al, Spring Irrigation Reduces the Frequency and Intensity of Summer Extreme Heat Events in the North China Plain, Geophysical Research Letters (2024). DOI: 10.1029/2023GL107094

Age-related changes in skin may contribute to melanoma metastases

Age-related changes that cause the skin to stiffen and become less elastic may also contribute to higher rates of metastatic skin cancer in older people, according to research by investigators.

 The study, published March 12 in Nature Aging, shows that increased stiffness in aging skin increases the release of a protein called ICAM1. Increased ICAM1 levels stimulate blood vessel growth in the tumor, helping it grow. It also makes the blood vessels "leaky," enabling tumor cells to escape and spread throughout the body more easily.

The discoveries might also lead to new approaches to treating other age-related cancers. Previous therapies targeting growth factors that contribute to angiogenesis have failed in many tumor types, including melanoma. But ICAM1 provides a promising new target.

Nature Aging (2024).

• Age-Related Lung Changes Provide Pathway for Metastatic Growth of D...
• Age is a primary determinant of melanoma treatment resistance, two ...

How invisible presences hijack the social counting brain in Parkinson's disease

If you had to estimate the number of people in a room, without counting them one by one, by nature you would overcount them. That's because—simply put from a Darwinian perspective of how we have evolved—it's better to overcount potentially harmful agents and predators than to underestimate them. This overcounting social behavior is shown to be true in humans as well as animals. It's certainly better to detect too many tigers (even if absent) during a jungle excursion than to miss a hungry one.

Now,  neuroscientists show that if you experience hallucinations, especially when related to an illness like Parkinson's disease, then you will overestimate the number of people in a room to a greater degree. They also show that if you have hallucinations but are asked to estimate the number of boxes in a room, which are inanimate control objects, then no extra overestimation occurs, shedding light on the social nature of this overcounting.

The results are published in Nature Communications.

The fact that patients of Parkinson's disease have a much higher over-estimation in counting people is mind-blowing because Parkinson's disease is classically viewed as a movement disorder.

This new work shows that Parkinson's may also be a perceptual disorder, especially of social stimuli, and that invisible presences in Parkinson's disease may impair even more the counting social brain.

The category of hallucinations investigated by the neuroscientists is called presence hallucinations, for which people report an invisible presence next to them, even though no one is there. Such hallucinations are considered to be minor compared to visual hallucinations, for instance. They may be experienced early on in patients with Parkinson's disease, sometimes even before diagnosis. Presence hallucinations are also a known early marker of cognitive decline in Parkinson's disease.

The results of the study support the idea that the invisible presence (and related brain mechanisms) are responsible for this overcounting of people. When presence hallucinations are experienced—either due to disease or induced artificially—this extra presence gets subconsciously translated into an over-estimation of the number of people we think we see. In essence, the invisible presence gets added in the counting process, but only in counting people.

Nature Communications (2024).

https://www.nature.com/articles/s41467-024-45912-w

Rainforest's next generation of trees threatened 30 years after logging

Rainforest seedlings are more likely to survive in natural forests than in places where logging has happened—even if tree restoration projects have taken place, new research shows. The work appears in Global Change Biology.

Scientists monitored over 5,000 seedlings for a year and a half in North Borneo.

They studied a landscape containing both natural forest and areas logged 30 years ago—some of which were recovering naturally, while some had been restored by methods including tree planting.

A drought had triggered "mast fruiting" across the region, with trees simultaneously dropping fruit en masse and new seedlings emerging.

At first, both natural forest and restored forest had similarly high numbers of seedlings, compared to naturally recovering forest—suggesting restoration activities enhanced fruit production.

But these benefits did not last: low seedling survival in the restored forest meant that by the end of the study, similarly low numbers of seedlings remained in restored and naturally recovering forest. Seedling populations remained higher in natural forest.

Together, these results show that regeneration may be challenged by different factors depending on the restoration approach—seed availability in naturally recovering sites and seedling survival in sites where planted trees have matured. These differences may have longer-term implications for how forests can deliver key ecosystem services such as carbon sequestration.

Bornean tropical forests recovering from logging at risk of regeneration failure Running Title: Seedling responses to logging and restoration., Global Change Biology (2024).

A coral superhighway in the Indian Ocean

New research has revealed that, despite being scattered across more than a million square kilometers, remote coral reefs across the Seychelles are closely related. Using genetic analyses and oceanographic modeling, researchers have demonstrated for the first time that a network of ocean currents scatter significant numbers of larvae between these distant islands, acting as a "coral superhighway."

This discovery is very important because a key factor in coral reef recovery is larval supply. Although corals have declined alarmingly across the world due to climate change and a number of other factors, actions can be taken at local and national scale to improve reef health and resilience.

These actions can be more effective when we better understand the connectivity between coral reefs, by—for instance—prioritizing conservation efforts around coral reefs that act as major larval sources to support regional reef resilience.

The researchers collaborated with a wide range of coral reef management organizations and the Seychelles government to collect coral samples from 19 different reef sites. A comprehensive genetic analysis revealed recent gene flow between all sample sites—possibly within just a few generations—suggesting that coral larvae may be frequently transferred between different populations. The results also hinted at the existence of a new cryptic species of the common bouldering coral, Porites lutea.

The genetic analyses were then coupled with oceanographic modeling, simulating the process of larval dispersal. These simulations allowed researchers to visualize the pathways coral larvae take to travel between reefs across the wider region, and determine the relative importance of physical larval dispersal versus other biological processes in setting coral connectivity.

This revealed that dispersal of coral larvae directly between reefs across the Seychelles is highly plausible. For example, coral larvae spawned at the remote Aldabra atoll could disperse westwards towards the east coast of Africa via the East African Coastal Current. From here, they would then travel north along the coast, with some potentially even reaching the South Equatorial Counter Current, which could bring them eastwards again back towards the Inner Islands of Seychelles.

While these long-distance dispersal events are possible, it is likely that much of the connectivity between remote islands across the Seychelles may be established through "stepping-stone" dispersal. This suggests that centrally located coral reefs in Seychelles, and possibly East Africa, may play an important role in linking the most remote islands.

Integration of population genetics with oceanographic models reveals strong connectivity among coral reefs across Seychelles, Scientific Reports (2024). DOI: 10.1038/s41598-024-55459-x

New research shows turbulent flows can be caused by minute triggers

We experience turbulence every day: a gust of wind, water gushing down a river, or mid-flight bumps on an airplane.

Although it may be easy to understand what causes some kinds of turbulence—a felled tree in a river or a bear splashing around for salmon—there is now evidence that a very small disturbance at the start can have dramatic effects later. Instead of a tree, think of a twig—or even the swerving motion of a molecule.

The butterfly effect

A butterfly flaps its wings in Brazil, which later causes a tornado in Texas. Although we may commonly use the phrase to denote the seeming interconnectedness of our own lives, the term "butterfly effect" is sometimes associated with chaos theory. Researchers said their work represents a more extreme version of the butterfly effect, first described by mathematician and meteorologist Edward Lorenz in 1969.

What researchers have learned is that in turbulent systems, a very small disturbance at one point will have an amplified effect at a finite point in the future, but through a mechanism that is faster than chaos.

Although the mathematical mechanism for this amplification, known as spontaneous stochasticity, was discovered about 25 years ago. The fact that the random motion of molecules, responsible for the everyday phenomenon of temperature, could generate spontaneous stochasticity was not known before this work.

Thinking back on the twig in the river, while you might notice a small disturbance where the water flows over the twig, you wouldn't expect it to create a great deal of turbulence (via eddies and swirls) downstream. Yet that is precisely what this new paper shows. The mechanism is known as spontaneous stochasticity, because the randomness arises even though the fluid motion was expected to be predictable.

Furthermore, it would be impossible to pinpoint the twig that had originally set the eddies and swirls in motion. In fact, there may be no disturbance in the water flow where the twig is located at all.

The research team's findings also showed that spontaneous stochasticity happens regardless of the initial disturbance. Whether it's a twig, a pebble, or a clod of dirt, the randomness you get on a large scale is the same. In other words, the randomness is intrinsic to the process.

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There exists a fundamental limit to what can be predicted with turbulence," according to researchers. "You see this with weather forecasts; there is always a fundamental source of randomness. The precise sense in which this unpredictability was inevitable wasn't fully understood before this work."

It's that randomness that makes it so hard to accurately predict the weather more than a few hours in advance. Meteorological stations sample weather in select locations, and computer simulations stitch them together, but without knowing the exact weather everywhere right now, it's hard to predict the exact weather everywhere in the future. This paper hints at the possibility that fundamental limits will always exist because randomness will always show up.

There may also be implications in astrophysics research. Scientists already understand that computer simulations of how galaxies are formed and how our universe evolved are sensitive to noise. Often, the behaviours of stars, planets, and galaxies cannot be easily explained and may be attributed to the kinds of microscopic noise that researchers have uncovered now.

Dmytro Bandak et al, Spontaneous Stochasticity Amplifies Even Thermal Noise to the Largest Scales of Turbulence in a Few Eddy Turnover Times, Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.132.104002. On arXiv: DOI: 10.48550/arxiv.2401.13881

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Jets release heat, water vapour, and particulate matter that can produce thin clouds in the sky, known as “contrails”. When numerous flights pass through some areas, these contrails can form clouds that absorb radiation escaping from the surface, acting as blankets floating above the Earth.

Study finds rerouting of airplanes to reduce contrails not as expensive as thought

A small team of environmental scientists has found via simulations that rerouting commercial airplanes to reduce contrails would be less expensive than previously thought. In their study, published in the journal Environmental Research: Infrastructure and Sustainability, the group used data from prior studies to create simulations of airplanes routed to prevent the development of contrails.

Prior research has shown that high-altitude airplanes are disproportionate contributors to climate change due to the multiple ways they impact the environment. In addition to the greenhouse gases they emit, jets that fly at high altitudes can also create contrails, white vapor trails of ice, water vapour and particulate matter.

When several planes fly in the same general area over the same period of time, the contrails can combine, leading to the formation of cirrus clouds, which can act like a blanket, holding in heat. Prior research has shown that this accounts for approximately 35% of the total aviation contribution to global warming.

Prior research has also shown that just 2%–10% of flights create approximately 80% of contrails. And because rerouting of jet planes can prevent the creation of contrails, researchers have suggested that the commercial aviation industry could greatly reduce its environmental footprint by doing so. But some argue that doing so would be too expensive to justify its cost.

To find out if that might be the case, American Airlines, working with another team of researchers last summer, used weather and satellite data to create software models and AI prediction tools to determine whether it was feasible to divert planes from airspace that would lead to contrail formation. They found that it appeared possible to reduce contrail formation by approximately 54%.

In this new effort, the research team used the same data to create simulations of 85,000 high-altitude flights and found that reducing contrails by 73% would raise fuel costs by just 0.11% and overall operating costs by just 0.08%. They also noted that rerouting aircraft under such a scenario would only involve 14% of all flights.

 Alejandra Martin Frias et al, Feasibility of contrail avoidance in a commercial flight planning system: an operational analysis, Environmental Research: Infrastructure and Sustainability (2024). DOI: 10.1088/2634-4505/ad310c

Progesterone protects babies from preterm birth in women with a short cervix, research shows

Preterm birth, defined as birth prior to 37 weeks, remains a serious problem with far-reaching consequences. Approximately 13.5 million children worldwide are born preterm each year. Children who are born preterm are at higher risk for, both physical and developmental, lifelong complications. Preventing preterm birth is therefore a major priority.

At around 20 weeks of pregnancy women with a short cervix have an increased risk of preterm birth. Preventing preterm birth in pregnant women with a short cervix is a crucial step in protecting the health of the child. Research now shows that, in pregnant women with a short cervix around 20 weeks, progesterone is better than a cervical pessary at reducing the risk of severe preterm birth. This study was published in the BMJ.

This is an important improvement that can contribute to the reduction of preterm births and the associated complications, such as an increased risk of infant mortality and long-term health problems for the child.

Researchers investigated the best treatment for women with a cervical length shorter than 25 mm at the 20-week ultrasound scan. A total of 25 centers across the Netherlands participated in this study.

The results of this study show that progesterone is more effective than a pessary in reducing extreme preterm birth. This study underlines the importance of measuring the length of the cervix during the 20-week ultrasound scan and informing women with a cervix shorter than 25 mm about the possibility of treatment with progesterone. For women with a cervical length between 25 mm and 35 mm, there was no significant difference in the number of complications due to preterm birth between the group taking progesterone and the group using a pessary.

Cervical pessary versus vaginal progesterone in women with a singleton pregnancy, a short cervix, and no history of spontaneous preterm birth at less than 34 weeks' gestation: open label, multicentre, randomised, controlled trial, The BMJ (2024). DOI: 10.1136/bmj-2023-077033

Study finds no persistent cough in four out of five individuals with tuberculosis in Africa and Asia

More than 80% of patients with tuberculosis, the world's most deadly infection, do not have a persistent cough, despite this being seen as a key symptom of the disease. The infection is predominantly transmitted by coughing, but probably also through simply breathing.

Researchers analyzed data on more than 600,000 individuals in Africa and Asia and found that 82.8% of those with tuberculosis had no persistent cough and 62.5% had no cough at all. These results are published today in The Lancet Infectious Diseases.

The  results indicate the probable reason why, despite huge efforts to diagnose and treat the disease, the tuberculosis (TB) burden across Africa and Asia is hardly declining.

A persistent cough is often the entry point for a diagnosis, but if 80% of those with TB don't have one, then it means that a diagnosis will happen later, possibly after the infection has already been transmitted to many others, or not at all.

 Prevalence of subclinical pulmonary tuberculosis in adults in community settings: an individual participant data meta-analysis, The Lancet Infectious Diseases (2024). DOI: 10.1016/S1473-3099(24)00011-2

Sugar-coated gold nanoparticles can quickly eliminate bacterial infections, no antibiotics required

If left to their own devices, bacteria on our teeth or wounded skin can encase themselves in a slimy scaffolding, turning into what is called biofilm. Oral biofilms, also known as plaques, formed by bacteria such as Streptococcus mutans can cause significant tooth decay. Wound infections, which are commonly caused by Staphylococcus bacteria, can greatly delay the healing process. In either case, the densely packed network of proteins and carbohydrates within biofilms can prevent antibiotics from reaching microbes throughout the affected area.

But that isn't the extent of the issue posed by biofilms. Not only are they difficult to remove, but they are troublesome to discern in the first place.

These bacteria wreak havoc on our tissue and, being shielded from antibiotic medication by the slime, are difficult to dislodge. A new strategy may offer a simple way to break up the muck and destroy the bacteria.

This new research identified a solution to knock out both problems with one stone: gold.

Researchers have developed sugar-coated gold nanoparticles that they used to both image and destroy biofilms.

Gold is nontoxic and readily converts energy from light sources into heat, making it a prime candidate for photothermal therapy, a strategy that utilizes the heat from nanoparticles to kill nearby pathogens. In addition to generating heat, the nanoparticles emit detectable ultrasound waves in response to light, meaning that gold particles can be visualized using a technique called photoacoustic imaging.

In the new study, the authors encapsulated gold spheres within larger golden cage-shaped nanoparticles to optimize their response to light for both therapeutic and imaging purposes. To make the particles appealing to bacteria, they coated them in dextran, a carbohydrate that is a common building block of biofilms.

In a study published in the Journal of Clinical Investigation, the authors demonstrated the diagnostic and therapeutic potential of the nanoparticles on the teeth and wounded skin of rats and mice, eliminating the biofilms in as little as one minute and outperforming common antimicrobials. 

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With this platform, you can bust biofilms without surgically debriding infections, which can be necessary when using antibiotics. Plus, this method could treat patients if they are allergic to antibiotics or are infected by strains that are resistant to medication. The fact that this method is antibiotic-free is a huge bonus. 

The researchers assessed their strategy by applying the gold nanoparticles atop S. mutans-infected teeth from ex vivo rat jaws.

In a photoacoustic imaging test on the teeth, the nanoparticles emitted signals that came through loud and clear, allowing the team to see precisely where biofilms had taken up the dextran-coated particles on the teeth.

Then, to evaluate the particles' therapeutic effect, they irradiated the teeth with a laser. For comparison, they treated other infected teeth samples with the topical antiseptic chlorhexidine.

The team observed a stark contrast in the outcomes of the two treatments, with the photothermal therapy being nearly 100% effective at killing biofilms, while chlorhexidine did not significantly diminish the viability of bacteria.

The treatment method is especially fast for the oral infection.

Evaluations conducted on mice with open wounds in their skin, infected with Staphylococcus aureus, were similarly successful, as heat generated by nanoparticles greatly outperformed another antimicrobial agent called gentamicin. Here, the researchers also measured and noted a rise in temperature of 20°C localized to the biofilm, not causing any apparent damage to surrounding tissue.

 Maryam Hajfathalian et al, Theranostic gold-in-gold cage nanoparticles enable photothermal ablation and photoacoustic imaging in biofilm-associated infection models, Journal of Clinical Investigation (2023). DOI: 10.1172/JCI168485

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Astronauts experience 'space headaches'

Space travel and zero gravity can take a toll on the body. A new study has found that astronauts with no prior history of headaches may experience migraine and tension-type headaches during long-haul space flight, which includes more than 10 days in space. The study was published in Neurology.

Changes in gravity caused by space flight affect the function of many parts of the body, including the brain.

The vestibular system, which affects balance and posture, has to adapt to the conflict between the signals it is expecting to receive and the actual signals it receives in the absence of normal gravity. This can lead to space motion sickness in the first week, of which headache is the most frequently reported symptom. This new study shows that headaches also occur later in space flight and could be related to an increase in pressure within the skull.

The study involved 24 astronauts from the European Space Agency, the U.S. National Aeronautics and Space Administration (NASA) and the Japan Aerospace Exploration Agency. They were assigned to International Space Station expeditions for up to 26 weeks from November 2011 to June 2018.

Prior to the study, nine astronauts reported never having any headaches and three had a headache that interfered with daily activities in the last year. None of them had a history of recurrent headaches or had ever been diagnosed with migraine.

Of the total participants, 22 astronauts experienced one or more episodes of headache during a total of 3,596 days in space for all participants.

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Astronauts completed health screenings and a questionnaire about their headache history before the flight. During space flight, astronauts filled out a daily questionnaire for the first seven days and a weekly questionnaire each following week throughout their stay in the space station.

The astronauts reported 378 headaches in flight. Researchers found that 92% of astronauts experienced headaches during flight compared to just 38% of them experiencing headaches prior to flight.

Of the total headaches, 170, or 90%, were tension-type headache and 19, or 10%, were migraine.

Researchers also found that headaches were of a higher intensity and more likely to be migraine-like during the first week of space flight. During this time, 21 astronauts had one or more headaches for a total of 51 headaches. Of the 51 headaches, 39 were considered tension-type headaches and 12 were migraine-like or probable migraine.

In the three months after return to Earth, none of the astronauts reported any headaches.

This research does not prove that going into space causes headaches; it only shows an association. A limitation of the study was that astronauts  reported their own symptoms. 

https://www.neurology.org/doi/10.1212/WNL.0000000000209224

Researchers discover plant temperature sensor molecule: The Rain Tree folds its leaves in the rain

A research group led by Professor Minoru Ueda and Graduate Student Yuki Muraoka of the Graduate School of Science at Tohoku University announced that they have clarified the identity of temperature-sensitive ion channels in plants. Focusing on the phenomenon of the legume tree Samanea saman (also known as the Rain Tree), which folds its leaves when it rains, the researchers found that a decrease in leaf temperature triggers the folding movement. Aside from the temperature effect on leaf folding, the research group also found that the ion channel SPORK2, which is present in cells at the base of the leaf, functions as a sensor molecule to detect temperature changes. These findings are expected to lead to the elucidation of the temperature-sensing mechanism in plants and were published in the November 28 issue of the journal Current Biology.

Temperature sensing is an essential function of all living organisms. Animals, including humans, use so-called transient receptor potential (TRP) channel molecules to sense temperature. These channel molecules are ion channel proteins that transport ions across cell membranes. They also act as temperature-sensing molecules because their function changes in response to temperature variation. By contrast, plants do not have temperature-sensing molecules such as TRP channels. Therefore, the mechanism by which plants sense temperature has been a mystery.

In this study, the research group focused attention on the fact that S. saman, which performs nyctinasty by folding its leaves at night and opening them in the morning, also folds its leaves when it rains. According to another report in 2018, nyctinasty in S. saman is regulated by SPORK2, an ion channel found in cells at the base of the leaf. This time, the research group found that this leaf folding is also triggered by temperature changes. They also found that SPORK2, like the TRP channel, changes its ion transport activity in response to temperature. Genes similar to SPORK2 (orthologs: genes derived from a common ancestral gene through species divergence) are found in other plants aside from S. saman.

Ion channels are proteins that form holes in the cell membrane through which ions are allowed to pass. The TRP channel creates holes for sodium and calcium ions, whereas SPORK2 generates holes for potassium ions. The activities of SPORK2 orthologs in Arabidopsis thaliana were also examined and they were found to be temperature-sensitive ion channels.

Crop production has been severely affected by climate change. Shedding light on the mechanisms by which plants adapt to temperature changes is an urgent issue for stable food production.

https://www.cell.com/current-biology/abstract/S0960-9822(23)01458-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982223014586%3Fshowall%3Dtrue

Part 2